Expression patterns of high-mobility group genes during tooth development

Abstract

The high-mobility group (Hmg) superfamily comprises three nuclear protein families, Hmga, Hmgb and Hmgn, which regulate cell proliferation and transcription of several genes during development. However, there are only few reports on the expression of Hmg genes in developing teeth. The aim of this study was to examine the expression pattern of the Hmg genes, including Hmga1, Hmga2, Hmgb1, Hmgb2 and Hmgn1 in developing teeth at the cap stage. The expression pattern of the Hmg genes, including Hmga1, Hmga2, Hmgb1, Hmgb2 and Hmgn1 was examined in developing mouse teeth at the cap stage by in situ hybridization assay. The strong expression of Hmga1, Hmga2, Hmgb1 and Hmgn1 was detected in the dental epithelium except in the enamel knot. We found a positional match among the Hmg gene expression, non-Hmg gene expression and cell proliferation. The most prominent cell proliferation in the lingual dental epithelium where the expression of Hmg genes overlapped the most; the total number of non-Hmg genes expressed was higher in the non-enamel knot than in the enamel knot. These results suggest the possible roles of Hmg proteins in regulating epithelial cell proliferation and transcription of other genes during tooth development.